A free-space measurement system in the 2-JBGHz frequency range is used to measure the reflection and transmission coefficients of planar samples. The complex electric permittivity and the magnetic permeability are calculated from the measured values of S11 and S21. The measurement system consists of broadband transmit and receive antennas, a network analyzer, mode transitions, and a computer. Error due to multiple reflections between antennas via the swjace of the sample are corrected by using a free space T.R.L. calibration technique.Peer ReviewedPostprint (published version